Process of making alpha-oxyanthraquinone.



No. 755,801. I

UNIT D STATES Patented March 29, 1904.

PATENT OFFICE.

ROBERT E. SCHMIDT, .OF ELBERFELD, AND PAUL TUST, OF VOHWINKEL, GERMANY, ASSIGNORS TO FARBENFABRIKEN OF ELBERFELD CO., OF NEW YORK, N. Y., A CORPORATION OF NEW YORK.

PROCESS OF MAKING ALPHA-OXYANTHRAQUINONE.

SPECIFICATION forming part of Letters Patent No. 755,801, dated March 29, 1904.

Application filed December 10, 1903. Serial No. 184,671. (No specimens.)

To obi/Z whom it may concern:

Be it known that we, ROBERT E. ScHMInT, doctor of philosophy, chemist, residing at Elberfeld, and PAUL TUsT, chemist, residing at 5 Vohwinkel, near Elberfeld,Grermany, (assignors to the FARBENFABRIKEN OF ELBERFELD COMPANY, of New York,) have invented a new and useful Improvement in Processes of Making Alpha-Oxyanthraquinone; and we hereby O declare the following to bea clear and exact description of our invention.

Our new process consists in causing alkaline earths to act on anthraquinone-alpha-sulfonic acid or its salts, which can be obtained by the I 5 action of sulfonating agents on anthraquinone in the presence of mercury or mercury compounds, as is described in the United States Letters Patent No. 743,664, dated November 10, 1903. By means of this process alpha-oxy- IO anthraquinone (erythrooxyanthraquinone) is obtained in a pure state.

In carrying out our invention we can proceed as follows, the parts being by Weight: In an autoclave provided with a stirrer a mixture =5 of twenty-five parts of the potassium salt of anthraquinone-alpha-sulfonic acid, eighteen part-s of calcium hydroxid, (Ca [OH]2,) and four hundred parts of water is heated to 190 centigrade for from three to four hours. On

3 acidulating the mixture while boiling with hydrochloric acid the alpha-hydroxyanthra quinone is precipitated in a pure state. The process proceeds in an analogous manner if other alkaline earths or mixtures of these 35 bodies, or if other salts of the anthraquinonealpga-sulfonic acid, or the free acid itself, be use Having now described our invention and in what manner the same is to be performed, what we claim as new, and desire to secure by Letters Patent, is

1. The new process for producing alphahydroxyanthraquinone, which process consists in first heating an aqueous mixture containing anthraquinone-alpha-monosulfonic acid and an alkaline earth, and then isolating the resulting alpha-hydroxyanthraquinOne from the reaction mass, substantially as hereinbefore described.

2. The new process for producing alphahydroxyanthraquinone, which process consists in first heating an aqueous mixture containing anthraquinone-alpha-monosulfonic acid and a mixture of alkaline earths, and then isolating nesses. c

' ROBERT E. SCHMIDT.

PAUL TUST.

Witnesses:

OTTO KoNIG, J. A. RITTERsHAUs. 

